List trace events for a given filter, ordered by (wall_time, mono_time, id).

Pagination is cursor-based (keyset). Clients fetch the first page with no cursor; when meta.next_cursor is non-null, pass it back in the next request to fetch the subsequent page. Stable under concurrent writes — new events landing at the tail won't cause duplicates or gaps when paginating forward. Cursors are opaque base64; format may change without notice.